Core drill



Feb. 4, 3.941. J. H. HOWARD ETAL CORE DRILL Filed 0H,. 14, 1938 2 Sheetselm-net 1.

M Z 9 m 3 C W z w 9 "k w 3 4 Z w w \v Vv a 3 a J \QAAAAAA Feb. 4, 1941. .L H HOWARD ETAL CURE DRILL m m////////// V/A// w 4 Q m w .q r 2 w 2 w M E g? j w a 5 l M. w Q a w V///////////A7//V////V////////////// 2 Patented Feb. 4, 1941 PATENT OFFICE cons mum.

John H. Howard, Whittier,

and Alfred 0. Catland, Alhambra, Calif.; said Catland assignor to Globe Oil Tools Company, a corporation of California Application October 14, 1938, Serial No. 234,908 5Claims. (Cl. 2255-72) This invention relates to well drilling tools and relates more particularly to core drills for use in the rotary method of well drilling. A general object of the invention is to provide an improved 5 core drill embodying an inner barrel of novel construction and operation.

Rotary core drills embodying floating inner barrels have gone into extensive use. The inner core receiving barrels of such drills are rotatably 10 supported in the outer barrels in order that they may float or remain non-rotatable with the core during the core taking drilling operations. Quite frequently the inner barrel of .a core drill of the character referred to rotates during the ll core cutting operation due to excessive friction at its bearings and other causes. The rotation of the inner core receiving barrel grooves and burns the core and oftentimes shatters the core.

, Another object of this invention is to provide a core drillembodying a floating inner barrel provided withnovel means for resisting rotation during the drilling or the core taking operation.

Another object of this invention is to provide a core drill of the character mentioned in which 25 the flow of circulation fluid is utilized to resist or prevent rotation of the inner barrel.

Another object of this invention is to provide a core drill of the character mentioned in which a free circulation of fluid is maintained at all 3 times.

Another object of this invention isto provide a core drill of the class referred to embodying a novel sectional inner barrel or core receiving barrel that is simple and easy to assemble and 35 that is inexpensive to manufacture. I

Another object of this invention is to provide a core drill of the so-called wire line type in which latches for the retention of the inner barrel are unnecessary and may be dispensed with, thus simplifying the construction and rendering theremoval of the inner barrel simple and easy.

. A further object of this invention is to provide a core drill of the character mentioned in which the means for holding the inner barrel against 45 rotation serves to assist .in holding the. sections of the inner barrel in assembled relation.

The various objects and features of our invention will be fully. understood from the following detailed description of typicalpreferred forms and a plications of our invention, through out which description reference is made to the accompanying drawings, inwhich:

Fig. 1 is a central longitudinal, detailed sectional vlewof one core drill oi'the invention show- 5 ing the inner barrel in elevation and portions earth formation. In the typi of the outer barrel in elevation. Fig. 2 is an enlarged fragmentaryside elevation of the inner barrel. Fig. 3 is a transverse detailed sectional view taken as indicated by line 3-3 on Fig. 2. Fig. 4 isan'enlarged fragmentary longitudinal 5 detailed sectional view showing the inner barrel in elevation and illustrating the action of the fluid. Fig. 5 is a diagram further illustrating the action of the fluid on the vane and Fig. 6 is a central longitudinal detailed sectional view of 10 another form of drill. oi the invention with a portion of the inner barrel in elevation.

The form of the invention illustrated in Figs. 1 to 5, inclusive, of the drawings may be said to include, generally, an outer barrel III, a head II on the lower end of .the outer barrel H) for cutting a core, a sectional inner barrel l2 rotatably supported within the outer barrel l0 and means 13 associated with the inner barrel I! for resisting its rotation during thedrilllng or core taking operations.

The outer barrel I0 is adapted to be connected with the lower end of a-tubular rotary well drilling string to be rotated thereby. The

outer barrel I0 is an elongate structure or as- '25 sembly provided at itsupper end with means for connection with the drilling string. In the case illustrated a sub 15 is secured to the upper end of theouter barrel l0 and has a threaded pin 16 forfacilitating the connection of the outer barrel with the drilling string. A sub I! may be threaded on the lower end of the tubular outer barrel l0. The outer barrel III is of substantially uniform internal diameter and is connected with the drilling string through the medium of 85 the sub ii to receive the circulation fluid from.

the string.

The head II is secured to-the lower end of the barrel Ill, and is provided to malre an annular cut in the earth formation and to thus form a 40 core for receptionby the inner barrel ii. In: accordance with the broader aspects of the invention the head It may be of any suitable type or form. In theconstruction illustrated the head It includes a tubular body I! threadedly connected with a tubular sub I! which in tumis I threaded on the outer barrel sub' l'l. Cutting ele-' ments are provided on the b0 I8 to act on the embodiment of the invention illustrated in the drawings the cutting elements of the head II; are in the naturev of circumferentiallyspaced cutting blades 20 pro- Jecting downwardly and outwardly from the head II. A socket 2| is provided in the drill head I8 and the lower wall of the socket constitutes an upwardly facing internal shoulder in the head body. The lower end of the sub l3 forms a downwardly facing annular shoulder 22 spaced above the bottom wall of the socket 2!. The cutting blades 26 of the head H are operable to form a core thatis received in the head body l8 and v the inner barrel l2 with suitable clearance and make an annular cut that receives the drill with suitable clearance.

The core drill preferably includes means for trapping or retaining the core of earth formation. Any suitable type or form of core catcher or core catching means may be embodied in the tool. In the particular application of the invention illustrated a, core catcher of the type described and claimed in Patent No. 2,030,297, granted February 11, 1936, is arranged in the body I 8 of the head II. The core catcher includes a floating or rotatable sectional ring 23 supported on an annular internal shoulder 24 in the head body l8. A plurality of circumferentially spaced core gripping and supporting dogs 25 is provided on the ring 23. The dogs 25- are pivotally supported in notches in the ring 23 and are yieldingly urged The barrel I2 is disposed longitudinally in the outer barrel I II in concentric relation thereto and may be of substantial length to receive a long core. In accordance with the invention the inner barrel I2 is an elongate sectional structure. The improved inner barrel l2 includes a main elongate tubular part divided longitudinally on a diametric plane to constitute two complementary sections 21. The abutting or adjacent edges of the barrel sections 21 are connected to prevent leakage between the sections by lapped or offset shouldered joints 26. The tubular assembly of the sections 21 is of sufflcient internal diameter to receive the core with some clearance and has an external diameter less than the internal diameter of the outer barrel III to leave an annular fluid passage 29 through the outer barrel.- The lower portions of the barrel sections 21 are threaded to receive a bearing collar 30. If desired or believed necessary the collar 30 may be locked or secured against unthreading by any convenient or suitable means. The bearing collar 30 is received in the socket 2 I of the head body I! and may bear downwardly against the lower wall of the socket to support the barrel l2. The collar 36 is freely rotatable in the socket 2| and has extensive rotary bearing engagement in the socket to support the inner barrel l2 in the position where it is centrally and concentrically disposed within the outer barrel Ill.

Vertical or longitudinal grooves II are provided in the upper portions of the bearing collar 30 to connect the passage 26 with ports 32 in the drill head II. The upper portions of the several ports 32 are Joined or connected. The ports 32- serve to discharge the circulationfluid at the lower end of the drill head ll to flush the blades 23 and to provide the necessary circulation in the well. The collar 30 may carry a bearing ring 32 to oppose and bear on the shoulder 22. The lower portion of the bearing collar 30 may receive the core catcher ring 23 and the collar may be shaped to stop or limit the upward movement of the core catcher. I

The inner barrel l2 includes a valve V for preventing the entrance of the circulation fluid to the interior of the inner barrel. Any preferred or selected type 'of core catcher valve may be applied to the inner barrel l2. In the drawings we have illustrated a type of valve V that is described and claimed in Patent No. 2,058,154, granted August '1, 1933. The valve V includes a collar 34 threaded on the upper end of the tubular assembly of the barrel sections 21. Bayonet slots 35 are provided in the collar 34 and extend down- 7 wardly from the upper end of, the collar. The valve V further includes a head 36 partially received by the collar 34. The head 36 is provided with lugs 31 cooperating with the bayonet slots 35. A latch 38 is pivoted on the head 36 and cooperates with the vertical portion of 'one of the slots 35 to retain the head 36 in the position whereits lugs 31 cooperate with the lateral portions of the bayonet slots. The head 36 carries a valve means operable to prevent the downwardly flowing circulation fluid from entering-the inner barrel I2 and capable of permitting the free escape of fluid from the upper end of the inner barrel. The valve means embodied in the head 36 may be of the character illustrated in Fig.6 of the drawings. The collar 34 and the head 36. of the valve V have clearance with the internal wall of the outer barrel III to permit the flow of fluid downwardly through the passage 29. Vertical stabilizing ribs 39 may be provided on the collar 34 and the head 36 to assist in retaining the inner barrel l2 in a centralized position in the outer barrel Hi. It is to be observed that the bearing collar 3|! and the valve collar 34 serve to connect the upper and lower ends of the assembled barrel sections 21.

The means I3 is an important feature of the invention. The means l3 utilizes the force of the downwardly flowing circulation fluid to stop or resist rotation of the inner barrel 12 during the rotary drilling or coring operations. In accordance with the usual practice rotary mud or circulation fluid is pumped downwardly through the drilling string at a substantial pressure and flows through .the passage 23 to discharge from the ports 32. During the coring or drilling operations the outer barrel l0 and the'drilling string are rotated in the righthand direction indicated by the arrow A in Fig. 4. This rotation of the drilling string and the barrel l0 gives the circulation fluid a rotary or helical motion so that it flows downwardly through the annular passage 29 substantially as indicated by the arrowed lines B of flow in Fig. 4. The pitch or inclination of the lines of flow of the fluid through the passage 29 depends upon the pressure and velocity of the fluid and upon the rate of rotation of the string and the outer barrel III as will be more fully described. The means l3 includes a helical fln or vane 40 on the exterior of the inner barrel 1!. The vane 40 is pitched in the same direction as the path of flow of the fluid flowing through the passage 29 but, as illustrated in Fig. 4 of the drawings, ispitched at a greater angle to the vertical'than the lines of flow B of the fluid. The

the circulation fluid flows through the passage 29 in a rotary or spiral manner, the direction of flow being indicated by thearrowed lines B. The circulation iiuid acts on the vane 40 to exert a force indicated by the line F which force F is made up of the components X and Y. From an inspection of Fig. 5 it will be seen that the component X acts to urge the inner barrel l2 downwardly and to some extent acts to resist rotation of the inner barrel. The component Y acts in a direction counter to the direction of rotation A of the outer barrel l0 and operates to prevent or resist rotation of the inner barrel l2. It will be seen how the force Fexerted on the vane 40 throughout the length of the vane effectively holds the inner barrel I2 against rotation. The direction of the lines of flow B of the fluid and, therefore, the intensity of the force F depend upon the relative diam eters of the inner and outer barrels l2 and, Ill, the rate of flow of fluid through the passage 29, and'the speed of rotation of the outer barrel i2. With a high rate of flow of fluid through the passage .29 and a low rate of rotation of the barrel l2 the lines of flow B will be more nearly vertical or parallel with the longitudinal axis of the barrel l2. With a slower rate of flow of fluid and a higher speed of rotation of the outer barrel ID the angle between the direction of flow B of the circulation fluid and the longitudinal axis of the barrel Ill increases. Accordingly, the holding or non-rotative force F exerted on the barrel l2 by the action of the fluid on the vane 40 may be controlled or varied at will.

The character of the vane ll! and the mode of its attachment to the inner barrel I2 are features of the invention. The vane is in the nature of a length of wire of suitable gauge given a spiralled or helical form. Prior to the application of the vane fill to the. inner barrel l2 a spiralled groove 6i is formed in the assembled barrel sections 21. The groove 4! is of sufficient depth to partially receive the wire of the vane 40 but is not deep enough to materially weaken the inner barrel E2. The wire of the vane 40 is laid or arranged in the helical groove HI and the groove may hold or may assist in holding the wire vane 40 in shape. The vane 40 is preferably secured to the barrel l2 at one or more points. In the preferred construction the opposite end portions of the vane 40 are welded to the barrel sections 27 at 42. It will be observed that the vane 40 is simple and inexpensive and easy to install. The wire vane 40 being wrapped about the sections 21 throughout a substantial 'portion of their length serves to assist in holding the sections together.

Where the barrel I2 is of considerable length the vane 40 .engaging about the sections 2? throughout a substantial distance materially assists in holding the sections together.

In the operation of the core drill illustrated in Figs. 1 to 5, inclusive, the outer barrel I0 is secured to the lower end of a rotary well drilling string and is lowered into the well for operation. During the coring operation the string is rotated to turn the barrel I! in the direction indicated by the arrow A and rotary mud or circulation fluid is pumped down through the string. The circulation fluid flows down through the passage 29 and discharges from the ports 32 to flush the blades 20 and to provide circulation in the well. The blades 20 act on the earth formation to form an annular cut and leave a central upstanding c'ore. As the drilling progressesthis core is received in the inner barrel I2. The friction of 'the collar 30 engaging in the socket 2|, the other factors may tend to cause the barrel 12 to rotate with the outer barrel Ill. The circulation fluid passes through the annular passage 29 in a spiral course as indicated by the lines B and impinges against or acts on the vane '40 to exert the force F on the barrel S2. The force .F, and particularly the component Y of this force F, efiectively resists turning of the barrel l2 with the outer barrel Ill. The cont-act of the inner barrel or parts thereon with the core of earth formation may also resist rotation of the inner barrel. The inner barrel remains nonrotatable throughout the coring operation so that its engagement with the core does not score, groove, burn or otherwise injure the core. When a core of suflicient length has been cut. the drill is raised and the dogs 25 pivot downwardly and inwardly to grip the core. The dogs 25 cause the core to be broken free from the earth formation and support the core in the barrel l2 so that it is removed from the well in the drill.

Fig. 6 of the drawings illustrates the invention embodied in what is known as a wire line core drill. The drill illustrated in Fig. 6 may be said to include, generally, an outer barrel it, -a head II- on the lower end 'of the barrel 80, an inner barrel l2 and means l3 holding the inner barrel 12 against rotation and upward movement.

The barrel Ill may be identical with the above described barrel Ill. The head ll is secured to the lower end of the barrel IO In the construction illustrated the head ll is threaded- .to a sub I9 on the lower end of the outer barrel present The irmer barrel lleis arranged centrally and I longitudinally in the outer barrel W to receive the core cut by'the bit head I I. The inner barrell'i is an elongated tubular assembly comprising' a major intermediate portion longitudinally divided on a diametrie plane to have two sections 21. The abutting edges of the sections 21 may be similar to the abutting edges of the above described sections 2'l. A collar 30 is screw-threaded on the lower ends of the assembled sections 21 The collar 3i) may be locked against unthreading.

The lower portion of the collar 30 is received in and bears in the socket M to support the inner barrel I2 The lower end of the collar 30* may rest on the bottom wall of the socket 2| to support the inner barrel. The collar 30 is freely rotatable in the socket 2| whereby the inner barrel l2 may remain non-rotatable during the rotary drilling operation. Core catching and rel2. In the construction illustrated the core catcher includes a ring 23* arranged in the collar 30' and upwardly and inwardly projecting spring fingers carried by the ring 23". The ring 23 may be rotatable in the collar The flngers 25* are retracted as the core enters the inner barrel l2 and are adapted to grip and support the core when the drill is raised from the well.

A valve V is provided on the upper end of the inner barrel l2". The valve V may include a collar-like body 52 threaded'on the upper ends of the sections 21*. A valve seat 53 is provided in the valve body 52 and a ball 54 cooperateswith the seat 53. The ball 54 seats downwardly against the seat 53 to prevent the entrance of circulation fluid to the upper end of the barrel I2 and is adapted to rise from its seat and permit the escape of fluid from the barrel 12* as the core C is received therein. The valve body 52 is ported above the seat 53. A stem 55 is provided at the upper end of the body 52 and has an enlarged head 55. The stem 55 and its head- 56 are engageableby a suitable grappling tool (not shown) for removing the barrel l2 from the drill. It is to be observed that the collar 30" and the valve body 52 serve to connect the opposite ends of the barrel sections 21. The inner barrel I2 just described extends through the outer barrel III with substantial clearance, leaving an annular fluid passage 29*. The lower end of the passage 29 communicates with the opening in the sub l9 which in turn communicates with the ports 32 so that circulation fluid may pass down through the passage 29 to discharge from the ports.

The means l3 may be similar to or identical with the means 13 described above. The means I3 comprises a spiralled or helical vane 40 on the assembled barrel sections 21. The vane ll! preferably extends from the collar I'll) to the valve body 52. In practice the vane 40* may be a length of wire partially embedded in the helical groove in the sections 27. The opposite end portions of the wire vane 40 may be welded to the sections 21 at 42* The operation of the drill illustrated in Fig. 6 is as follows. The barrel l0 carrying the drill head ll may be attached to the lower end of a rotary well drilling string to be rotated in the well in the well known manner. When it is desired to obtain a core the barrel l2 is dropped, pumped or lowered through the string to come to rest in the position illustrated. in Fig. 6. Drilling is continued or resumed and the core is received in the opening 50 and the inner barrel I2". The circulation fluid pumped down through the drilling string flows through the passage 29 to discharge from the ports 32. The circulation fluid acts on the helical vane 4!) to exert a force corresponding to.the force F described above. The component X of this force F is downward and acts to hold the inner barrel l2 against upward movement while the force Y is counter to the direction of rotation of the outer barrel Ill and acts to hold the inner barrel l2! against turning. Thus the means l3 operates to hold the inner barrel l2 down in place to receive the core and acts to hold the inner barrel l2 against rotation. When a core oi! sufficient length has been obtained a grappling tool is lowered through the string on a wire line or cable and is engaged with the stem 55 and the head 56. In this manner the inner barrel l2 containing the core may be withdrawn from the drill and the drilling string. A new or second inner barrel l2- or a so-called plug bit may then be dropped or pumped down the drilling string to the operatingposition and the drilling may be resumed.

Having described only typical preferred forms and applications of our invention, we do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to ourselves any variations or modifications that may appear to those skilled in the-art, or fall within the scope of the following claims.

Having described our invention, we claim:

1. A rotary core drill comprising an outer barrel having a drill head on its lower end for cutting a core, a rotatably supported inner barrel in the outer barrel for receiving the core, there being an annular passage between the barrels. and a wire helically wound onto the inner barrel to extend from adjacent the upper end of the inner barrel to adjacent the lower end of the inner barrel and acted on by the fluid flowing downwardly through said passage to resist rotation of the inner barrel.

.2. In a core drill, an inner barrel divided longitudinally into two sections, and a wire helically arranged around the barrel to hold the sections together.

3. In a core drill, an inner barrel divided longitudinally into two sections, collars on the ends of the barrel holding the sections together, and a wire helically arranged around the barrel to hold the sections together.

4. A rotary core drill comprising an outer barrel to be connected with a fluid conducting drilling string and having a cutting head for cutting a core, an inner barrel arranged longitudinally in the outer barrel to receive the core and spaced from the interior of the outer barrel to leave an annular passage for conducting the circulation fluid, the inner barrel being longitudinally split into sections, means rotatably supporting the lower end of the inner barrel in the outer barrel, and a wire helically wrapped about the inner barrel to hold the sections together and to form a vane on the inner barrel acted upon by the fluid flowing through said passage.

5. In a core drill, an inner barrel for receiving the core and having a helical external groove, the inner barrel being longitudinally divided into sections, and a wire helically wrapped about the inner barrel to hold its sections togetherand to be received in the groove, the wire projecting from the groove to form an external helical vane on the barrel.

JOHN H. HOWARD. ALFRED C. CATLAND. 

